Toyota's revelation Tuesday that it will develop a new "plug-in hybrid" – which uses a wall socket at night to charge and relies on an electric motor to go many miles before sipping any gasoline – could presage a major shift in automotive technology, some industry analysts say.

Detroit's Big Three have each said the technology is being looked at – after years of outright dismissal. But Toyota's announcement was more significant because the company is presumed to have the technology to actually bring such cars to market, they say.

Toyota itself had steadfastly denied any interest in plug-in technology. A senior Toyota engineer told the Monitor early last year the company had little interest.

But gasoline prices have since soared to more than $3 a gallon. On Tuesday, the president of Toyota's North American subsidiary, Jim Press, said the company is looking at developing a plug-in vehicle that can "travel greater distances without using its gas engine." The technology would "conserve more oil and slice smog and greenhouse gases to nearly imperceptible levels".

The company is also developing flexible-fuel technology that could use E85 ethanol. If the two technologies were combined in one vehicle, it could help free the US from its oil dependence, some analysts say.

"When you combine plugging-in – which pushes fuel efficiency over 100 miles per gallon – with biofuels, then you're getting into multiple hundreds of miles per gallon," says Bradley Berman, publisher of hybridcars.com, a technology website. "It starts to look like a real here-and-now solution to oil dependence, air quality, and climate change."

Not everyone's convinced. Walter McManus, an industry analyst at the University of Michigan, says the technology may be too costly. "I don't think there's a huge market for them," he says.